601 research outputs found
A common haplotype lowers PU.1 expression in myeloid cells and delays onset of Alzheimer's disease
A genome-wide survival analysis of 14,406 Alzheimer's disease (AD) cases and 25,849 controls identified eight previously reported AD risk loci and 14 novel loci associated with age at onset. Linkage disequilibrium score regression of 220 cell types implicated the regulation of myeloid gene expression in AD risk. The minor allele of rs1057233 (G), within the previously reported CELF1 AD risk locus, showed association with delayed AD onset and lower expression of SPI1 in monocytes and macrophages. SPI1 encodes PU.1, a transcription factor critical for myeloid cell development and function. AD heritability was enriched within the PU.1 cistrome, implicating a myeloid PU.1 target gene network in AD. Finally, experimentally altered PU.1 levels affected the expression of mouse orthologs of many AD risk genes and the phagocytic activity of mouse microglial cells. Our results suggest that lower SPI1 expression reduces AD risk by regulating myeloid gene expression and cell function
Experimental studies of e + e -→ some charmless processes containing K S0 at √s = 3.773 and 3.65 GeV
We measure the observed cross sections for the charmless processes e + e -→K S0 K - K - K + π ++ c.c., K S0 K - π + η+c.c., K S0 K - π + π + π - η+c.c., K S0 K - K - K + π + η+c.c., K S0 K - K - K + π + π 0+c.c., K S0 K - ρ ++c.c. and K S0 K - π + ρ 0+c.c. We also extract upper limits on the branching fractions for ψ(3770) decays into these final states at 90% C.L. Analyzed data samples correspond to 17.3 pb-1 and 6.5 pb-1 integrated luminosities registered, respectively, at √s = 3.773 and 3.65 GeV, with the BES-II detector at the BEPC collider. © 2009 Springer-Verlag / Società Italiana di Fisica.published_or_final_versionSpringer Open Choice, 21 Feb 201
Search for ψ(3770)→ charmless final states involving η or π0 mesons
We search for ψ(3770) → π+π-η, K+K-η, pp̄η, ρ0π+π-η, K+K-π+π-η, pp̄π+π-η, pp̄K+K-η and pp̄K+K- π0 using data samples of 17.3 and 6.5 pb-1 integrated luminosities recorded at the center-of-mass energies of 3.773 and 3.65 GeV, respectively, by the BES-II detector operating at the BEPC collider. We obtain cross section measurements at both energies and upper limits on ψ(3770) decay branching fractions to the final states studied. © © Springer-Verlag / Società Italiana di Fisica 2010.published_or_final_versionSpringer Open Choice, 21 Feb 201
Pediatric campylobacteriosis in northern Taiwan from 2003 to 2005
<p>Abstract</p> <p>Background</p> <p>There has been a marked increase in the incidence of, and concern regarding, human <it>Campylobacter jejuni </it>and <it>C. coli </it>infections worldwide during the last decade. As the highest infectious disease control apparatus in Taiwan, we aimed to describe the character of <it>Campylobacter </it>isolates from infected children, as well as basic information about the patients, from December 2003 to February 2005.</p> <p>Methods</p> <p>A total of 894 fecal specimens were collected by several clinics and hospitals from children who had diarrhea, followed by plating onto selective media. Drug susceptibility test of the isolates from these specimens were conducted by disc diffusion method and their serotypes were also studied using commercial antisera made in Japan.</p> <p>Results</p> <p>The isolation rate of <it>Campylobacter </it>during these 15 months was 6.8% and was higher in winter (11.1%) than in other seasons. <it>C. jejuni </it>was the most prevalent (95.1%) species in northern Taiwan, comparable to other developed countries. Among the 61 <it>Campylobacter </it>isolates, most were resistant to tetracycline (93.4%), nalidixic acid (91.8%), ciprofloxacin (90.2%), and ampicillin (85.5%). Erythromycin-resistant isolates represented 3.3% of all isolates, suggesting that this drug may be the first choice for treatment. The serotypes of the 61 isolates were demonstrated and only 41.4% were typable.</p> <p>Conclusion</p> <p>In this study, the Taiwan CDC provided an epidemiological analysis of <it>Campylobacter </it>infection, including the isolation rate, age, seasonal distribution, antimicrobial drug susceptibility patterns, and serotypes of the isolates from pediatric patients in northern Taiwan from 2003 to 2005.</p
Intrahepatic biliary mucinous cystic neoplasms: clinicoradiological characteristics and surgical results
Increased expression of PHD3 represses the HIF-1 signaling pathway and contributes to poor neovascularization in pancreatic ductal adenocarcinoma
Background: Pancreatic ductal adenocarcinoma (PDAC) is known as one of the most malignant potential diseases with poor neovascularization. By comparing PDAC to hepatocellular carcinoma (HCC), which is well vascularized, we investigated the mechanisms and tumor biological significance of the poor neovascularization in PDAC. Methods: Surgical specimens from primary PDAC and HCC patients were immunohistologically stained to detect the expressions of CD105, CD44, HIF-1α, PHD3, and Siah2. We also used two PDAC and two HCC cell lines to compare the expressions of HIF-1α, PHD3, and CD44, as well as the production of VEGF in hypoxic condition. The role of PHD3 in regulating HIF-1α expression was further confirmed by siRNA knockdown in a PDAC cell line that highly expressed PHD3. Results: There were significantly fewer microvessels but more cancer stem cells in PDAC specimens compared to HCC specimens. The expression of CD105 was reversely related to the expression of CD44 in PDAC and HCC specimens. PDAC specimens also showed higher expressions of PHD3 but lower expressions of HIF-1α. Similarly, the expression of PHD3 was observed clearly in PDAC cell lines, but was almost completely negative in HCC cell lines. Hypoxic stimulation clearly enhanced HIF-1α expression and VEGF secretion in both HCC cell lines, but did not significantly change in PDAC cell lines. The knockdown of PHD3 in PDAC cells restored the hypoxic-induced HIF-1α expression, which accordingly stimulated the cells’ VEGF secretion. Conclusions: The enhanced expression of PHD3 might likely contribute to the poor neovascularization and affect the biological characterization in PDAC cancer cells
Oxygen Tension Modulates Neurite Outgrowth in PC12 Cells Through A Mechanism Involving HIF and VEGF
Cell-based approaches are a promising therapeutic strategy for treating injuries to the nervous system, but the optimal means to promote neurite extension and direct cellular behavior are unclear. Previous studies have examined the behavior of neural-like cells in ambient air (21% oxygen tension), yet these conditions are not representative of the physiological oxygen microenvironment of neural tissues. We hypothesized that neuronal differentiation of a model neural cell line (PC12) could be controlled by modulating local oxygen tension. Compared to ambient conditions, PC12 cells cultured in reduced oxygen exhibited significant increases in neurite extension and total neurite length, with 4% oxygen yielding the highest levels of both indicators. We confirmed neurite extension was mediated through oxygen-responsive mechanisms using small molecules that promote or inhibit HIF-1α stabilization. The hypoxic target gene Vegf was implicated as a neurotrophic factor, as neurite formation at 21% oxygen was mimicked with exogenous VEGF, and a VEGF-neutralizing antibody attenuated neurite formation under reduced oxygen conditions. These findings demonstrate that behavior of neural-like cells is driven by the oxygen microenvironment via VEGF function, and suggest promising approaches for future applications in neural repair
Identification of Antifreeze Proteins and Their Functional Residues by Support Vector Machine and Genetic Algorithms based on n-Peptide Compositions
For the first time, multiple sets of n-peptide compositions from antifreeze protein (AFP) sequences of various cold-adapted fish and insects were analyzed using support vector machine and genetic algorithms. The identification of AFPs is difficult because they exist as evolutionarily divergent types, and because their sequences and structures are present in limited numbers in currently available databases. Our results reveal that it is feasible to identify the shared sequential features among the various structural types of AFPs. Moreover, we were able to identify residues involved in ice binding without requiring knowledge of the three-dimensional structures of these AFPs. This approach should be useful for genomic and proteomic studies involving cold-adapted organisms
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